Burning the Midnight Oil

The Definition

To work late into the night, typically on a demanding project, study, or piece of writing. It implies a sense of deep focus and labor that extends far beyond the natural hours of daylight.

The Deep Dive

This is a literal piece of "junk knowledge" from the centuries before the flick of a light switch. In the pre-industrial world, the rising and setting of the sun dictated the rhythm of human life. For the average person, when it got dark, you went to sleep.

  • The Cost of Light: To work after dark was an expensive and physically taxing endeavor. You had to "burn" a fuel source—usually tallow (animal fat), whale oil, or olive oil—in a lamp or candle.

  • The "Midnight" Limit: Because oil was a precious commodity, only those with urgent work or scholarly ambitions would "waste" it past midnight.

  • The "Smell" of Learning: In the 17th century, the phrase was often used to describe the work of poets and philosophers. Their critics would say a poem "smelled of the oil," meaning it felt over-worked, scholarly, and artificial, as if it had been written during those weary, lamp-lit hours rather than in the "natural" light of day.

The phrase was immortalized by the English poet Francis Quarles in his 1635 work Emblems, where he wrote: "Wee burne our midnight oyle." By the time the industrial revolution brought gaslight and later electricity, the physical "oil" was gone, but the "burn" remained a badge of honor for the late-night overachiever.

Fast Facts

  • The Whale Oil Boom: In the mid-1800's, "burning the midnight oil" almost exclusively meant burning spermaceti oil from sperm whales, which provided the brightest, cleanest, and most expensive light available.

  • The "Lamp" to "Desk" Shift: Before the 1600's, the common phrase was "to smell of the lamp," a translation of the Ancient Greek lychnon ozein, used by Plutarch to criticize the overly rehearsed speeches of Demosthenes.

  • The Kerosene Transition: In the 1850's, the discovery of kerosene (coal oil) made "midnight oil" much cheaper for the working class, leading to a surge in nighttime literacy and self-education.

References

  • Quarles, F. (1635). Emblems, Divine and Moral.

  • Plutarch. (c. 100 AD). Lives of the Noble Grecians and Romans (Life of Demosthenes).

  • Ammer, C. (2013). The Dictionary of Clichés. Skyhorse Publishing.

  • The Oxford English Dictionary. (2026). Oil (n.) and Burn (v.). Oxford University Press.